1. Field of the Invention
The present invention relates generally to electron microscopes, and more particularly, to a semi-closed observational environment for an electron microscope.
2. Description of the Related Art
As known in prior art, while a conventional electron microscope is operated to observe an object, the object has to be a nonvolatile solid for further microscopic observation because of the limitation of the vacuum environment of the specimen chamber inside the electron microscope. If the object is volatile, such as liquid, gas, or other fluid, the object will generate a great amount of gas upon after being put into the vacuum specimen chamber, and thus, not only the electron beam of the electron microscope will fail to penetrate the object for successful imaging or experiment of electron diffraction, but also high-vacuum area, like electron beam gun, will lower its vacuum level or cause contamination therein, further damaging the microscope.
Limited to the vacuum environment, the conventional electron microscope could be operated for structural observation of solid substance inside the specimen chamber or for observation of dehydrated biological tissues only, like cells, bacteria, or viruses, neither for observation of any cell, bacterium, virus or the like having physiological functions under the fluid environment, absolutely nor for observation of biochemical reaction processes, like transcription between deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) inside the nucleus and translation between RNA and protein, microtubules inside the cytoplast, and of any vital biological phenomenon, like physiology of transduction at neuromuscular junctions.
Therefore, there must be a device that the live cell or tissue could be put therein and the device could be put into the specimen chamber of the electron microscope for observation.
Although some people proposed an environment inside the electron microscope for observation, such as Gai P. L. (Gai P. L., Microscopy & Microanalysis 8, 21, 2002). However, such design has the following drawbacks. It failed to keep the pressure of the specimen chamber close to the normal pressure or higher for observation and analysis, because the liquid under the liquid-gas equilibrium will instantly fully volatilize, thus requiring supplementary liquid for entry into the specimen chamber. However, such entry of supplementary liquid will cause serious problems of flow or uneven admixture of new and original specimens to result in inauthenticity of the observation. Moreover, the massive volatilized high-pressure vapor or the high-pressure gas injected into the gas chamber from outside will fill the space between the upper and lower pole pieces to cause more serious multiple electron scattering due to electrons impinging excessive gasiform molecules, further disabling successful imaging of the electron beam or experiment of electron diffraction. Furthermore, the specimen chamber in design fails to effectively control the amount of the injected liquid, causing excessive thickness of the liquid to further disable penetration of the electron beam through the specimen and thus disabling observation and analysis.
In view of above, after successive trials and experiments, the present invention is finally invented to improve the aforementioned drawbacks of the prior art and to receive general specimen or live cells for observation under the microscope.